Local methods involve taking the partial derivative of the output Y with respect to an input factor Xi: | ∂ Y ∂ X i | x 0 {\displaystyle \left|{\frac {\partial Y}{\partial X_{i}}}\right|_{{\textbf {x}}^{0}}} , where the subscript X0 indicates that the derivative is taken at some fixed point in the space of the input (hence the 'local' in the name of the class). Les méthodes locales impliquent de prendre la dérivée partielle de la sortie Y par rapport à une entrée Xi: | ∂ Y ∂ X i | x 0
